1. Field of the Invention
The present invention relates to a work station dealing with image data and, particularly, to a work station capable of batch storing and batch retrieving image data independently of a file system and also capable of directly transferring mass image data between a disk unit and input/output unit without going through a window memory.
2. Description of the Prior Art
With recent advanced computer technology, various information processing devices associated with computers have also made a great progress. For example, a single computer can process information of several users concurrently, and the users transfer information to the computer over data buses through terminals called "work stations". A variety of information includes character data, image pattern data and audio data, and recently various types of images are digitized through pattern recognition and transferred to a computer by way of work stations and data buses so that the image information is processed by the computer.
An example of conventional work stations dealing with image data is disclosed in publication: Nikkei Electronics, p. 156, published on May 23, 1983. FIG. 1 shows in block diagram the conventional image data work station system, with a small modification being made from the above citation, which includes a main processor 1, a memory 2 associated with the main processor 1, an image data output unit, e.g., printer, 3, an image data input unit, e.g., tablet, digitizer, etc., 4, a direct memory access controller (DMA controller) 5 which implements data transfer among the image data input unit, output unit and memory, a disk unit 6 for storing image data, vector data and other file data, and a disk controller 7 for controlling the disk unit 6. The work station further includes a graphic controller (graphic processor) 8, a window memory 9 for storing image information, an input unit, e.g., keyboard, 10 used by the operator for the interactive operation with the work station (this unit will be termed "operator input unit"), a bit-map display unit 11, and a frame memory 12 for storing bit-map information to be displayed on the display unit 11. The main processor 1, memory 2, DMA controller 5, disk controller 7, graphic processor 8 and window memory 9 are connected to a common bus 13, while the graphic controller 8, window memory 9 and frame memory 12 are connected to an image data bus 14 with the ability of fast data transfer. In the system configuration of FIG. 1, the devices located above the common bus 13 will be called "higher" devices, and those located below the common bus 13 will be called "lower" devices in the following.
The operation of the above arrangement is as follows. Initially, data supplied from the image data input unit 4 by way of the DMA controller 5 is stored in the window memory 9. If it is requested to display the data on the bit-map display unit 11, the graphic controller 8 creates a screen image in the window memory 9 and transfers it to the frame memory 12. In case of storing the input image data in the disk unit 6, the screen image is transferred directly from the window memory 9 to the disk unit 6. In another case of outputting the image information to the image data output unit 3, data is retrieved from the disk unit 6, the output image is developed in the window memory 9, and it is transferred to the output unit 3 by way of the DMA controller 5.
Some types of work station do not have one or both of the input and output units 3 and 4, and are merely operative to store and retrieve image data for the bit-map display unit 11 to/from the disk unit 6.
The conventional work station dealing with image data arranged as described above stores bulky image data as a file in the disk unit under a general-purpose operating system (OS) so that it is treated in file control. On this account, time needed for making access to image data in the file is dependent on the performance of the disk driver and general-purpose operating system, and this is in general a time consuming task.
In addition, image data transfer uses the common bus a great proportion of time, and it affects other processings considerably. For a system with an additive image input/output unit, image data is transacted through the window memory, and it has been difficult to deal with image data of a large frame size (e.g., A0 and A1 sizes).